Typebar drive mechanism

ABSTRACT

A typebar drive mechanism for a plurality of typebars has a drag link with a bellcrank and two associated links at the reciprocating end. A drive rail is rotatably mounted on the reciprocating end of the drag link so as to have a pushing edge that describes different paths during the outward and return movements of the reciprocating end of the drag link. A drive pawl is provided for each typebar; each pawl having a pushing tongue arranged to be actuated by the pushing edge during the outward stroke of the drive rail when the respective typebar has been selected. The pushing tongue is also arranged to be in a path other than that of the return movement of the pushing edge, so that the drive pawl of a next-selected typebar can be actuated before the drive rail has returned. The drag link and drive rail assembly can be adjusted in response to either type-shifting or the copy set.

o 2' United States atent [is] 3,643,772 Kittel et a1. Feb. 22, 1972 [54] TYPEBAR DRIVE MECHANISM 2,010,652 8/1935 Tauschek ..197/14 X Inventors: Arthur Kine; Kurt Chvaflinsky, bmh of 2,059,537 11/1936 Salzberger et a1. 197/17 wllhelmshaven Germany Primary ExaminerRobert E. Pulfrey 73 Assignee: Olympia Werke AG, Wilhelmshaven, Ger- Assistant Examiner-Stephen Pellegrino many Attamey-Spencer & Kaye [22] Filed: Feb. 2, 1970 57 ABSTRACT 1 1 pp 7,863 A typebar drive mechanism for a plurality of typebars has a drag link with a bellcrank and two associated links at the reciprocating end. A drive rail is rotatably mounted on the [30] Foreign Apphcahon Pnomy Data reciprocating end of the drag link so as to have a pushing cdge Feb. 1, 1969 Germany ..P 19 04 964.0 that describes different paths during the outward and return movements of the reciprocating end of the drag link. A drive [52] US. Cl ..197/14, 197/17 p is provided for each yp each p l h ving a p hing [511 Int. Cl. .3413 23/38, B41j 23/08 tongue arranged to be actuated y the Pushing edge during the [58 Field of Search ..197/17.14 Outward Stroke of the drive rail when the respective yp has been selected. The pushing tongue is also arranged to be in 56] References Cited a path other than that of the return movement of the pushing edge, so that the drive pawl of a next-selected typebar can be UNITED STATES PATENTS actuated before the drive rail has returned. The drag link and drive rail assembly can be adjusted in response to either type- 2,891,649 6/1959 Peterson ..197/14 Shifting or the copy Set 1,927,761 9/1933 Tauschek... 197/14 1,100,795 6/1914 Vogel 197} 14 10 Claims, 2 Drawing Figures PATENTEDFEB 22 I972 SHEET 1 BF 2 INVENTORS.

Ki'rtel Kurt Chvoflinsky $01 52 8 Arthur ATTORNEYS.

PATENTEUFEB 22 I972 SHEET 2 BF 2 INVENTORS.

Ar'rhur Kiflel Kurt Chvoflinsky BY WM F 2% ATTOR NEYS.

TYPEBAR DRIVE MECHANISM BACKGROUND OF THE INVENTION The present invention relates to a typebar drive mechanism for power-driven typewriters and similar machines in which the typebar movement is controlled by a continuously rotating shaft through a clutch release by the actuation of a keylever and is transferred by a drive crank to a drive pawl of the respective typebar mechanism. 1

In such power-driven typewriters it is necessary, in order to effectively utilize the possibilities of a power drive, that the machine accept and process a rapid sequence of strokes without malfunctions occurring due to lagging of parts of the machine. This also applies for machines controlled by punched tapes or the like, where the hardly unavoidable rhythmical irregularities occurring with manual operation are, of course, eliminated. It is, moreover, desirable to make the striking force regulatable in dependence on the type selection and the number of copies being typed.

For this purpose, devices are provided which permit the preselection of characters before the previously selected character has finished its printing cycle. This leads to substantial increases in the typing speed and, thus, to a saving of time. The entire typebar drive mechanism must be so designed that, on the one hand, no components of the selected mechanism impede the movement of the typebar mechanism in action by their position nor, on the other hand, are they themselves prematurely actuated and caused to move in an interfering manner. The entire transfer of movement must occur as smoothly and noiselessly as possible.

Proposals have become known to accomplish separation of stacked or similarly supplied groups of objects, particularly cards, without interference by the drive member effecting the displacement on its return path, in that the pushing edge is part of a coupler link. The curbed path of the respective coupling point is here utilized to guide the pushing edge in force-transmitting relationship with the pushed card edge when pushing it away and to a sufficient distance from the next card surface when it returns in the starting position. However, the problems of controlled preselection with additional means during an initiated operating step already in progress does not occur, since the simple automatic downward sliding of the cards in the stack under their own weight can not be counted in this respect.

In this known device, which meets the requirements for a mechanism for card separation, the arrangement for the typebar drive with preselection is not yet satisfactory.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device which permits with simple means, a preselection of a typebar mechanism with respect to a mechanism presently performing the printing movement with the best possible protection against malfunctions during the time overlap of the movement sequences at increased typing speeds together with substantial noise reduction and freedom from shocks.

This is accomplished, according to the present invention, in that a drive crank is provided having a rotatably disposed drive rail thereon whose pushing edge describes different curves during forward and return movement of the drive crank in such a manner that a pushing tongue of the preselected drive pawl latch for the next typebar mechanism remains untouched by the pushing edge returning into its starting position. The drive crank according to the present invention is a member of a known, four-sided linkage in the form of a four-bar drag link mechanism; the drive rail which is rotatably mounted on this drive crank being journaled to a coupler link via a connecting link.

In order not to interfere with the movement of a typebar drive mechanism presently performing the actual printing, and particularly in order to avoid interference from the portions of the next drive mechanism which has been brought in the preselect position on the return movement of the drive rail, a

further development of the present invention provides that the members of the drive crank, as well as the swing arm associated with the drive rail and the connecting link have a speed ratio so selected that the pushing edge of the drive rail performs different curves during forward and backward movement which together have a kidney shape.

To produce a perfect typing imprint it is necessary to have the working movements of the typebar drives always begin from a definite starting position of the components and to have them return to this position. For this reason, the typebar drive mechanism is provided with an extension on the crank arm for a crankpin in the form of a disc concentric with the main shaft, as well as a pivotally mounted catch lever with a detent roller which is pulled by a tension spring against the periphery of the disc and can there engage in a detent catch to produce a defined and reproducible stop position of the crank drive. In order to be able to influence the typebar with respect to its path of movement and its striking force, a further development of the present invention provides that the distance between the pushing edge, on the one hand, and the pushing tongue of the respective drive pawl, on the other hand, be adjustable. This is preferably accomplished according to the present invention by making the drive rail, which is permanently connected to a reciprocating drive crank by means of a shaft, adjustable by means of a swing arm adjustably fastened on this shaft and coupled with the connecting link against the coupler link.

The second regulating possibility is that the position of the crank swing is variable for changing the distance of the pushing edge from the respective pushing tongue in dependence on the type selection and on the number of copies produced, for which purpose an eccentric bushing is adjustably disposed on the crankpin which bushing is permanently connected with a pivot arm.

A preferred embodiment provides that the eccentric bushing is adjustable through a coupling connected, on the one hand, with the pivot lever and, on the other hand, with a disconnectable sliding block crank. In this case the sliding block crank is guided to be longitudinally movable and is provided with teeth into which a toothed transmission lever engages. This toothed lever is mounted on the switchable typebar segment bearer which can be pivoted by a setting and arresting lever disposed at the keyboard via a connecting rod joined to the two levers.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevation view of the crank drive and the drive rail of the typebar drive mechanism according to the present invention.

FIG. 2 is a perspective view of the typebar drive mechanism of FIG. 1.

FIG. 3 is a perspective view, partly in cross section, showing the main shaft, disc, crankpin and eccentric bushing of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a main shaft 2 is supported by frame 1 and driven through a switchable clutch (not shown), for example a one-revolution clutch such as disclosed in the Salzberger et al. U.S. Pat. No. 2,059,537, dated Nov. 3, I936.

Shaft 2 bears a disc 3 having a crankpin 4 and a rotatable eccentric bushing 4a, in which the rear end 5a of a coupler link 5 is disposed. The front end 5b of coupler 5 is pivotally connected with the upper end of an angular drive crank, such as bellcrank 6. This drive crank 6 is firmly attached to the one end ofa shaft 8 which passes transversely through the machine and which is rotatably mounted in the frame 1 of conventional construction. Crank 6 is further provided with a bearing 9 at its corner point, approximately at half its length, for a rotatably mounted swing shaft 10, which also passes transversely through the machine and is mounted with its other end in a bearing arm 6 fastened to shaft 8. The swing shaft 10 bears a drive rail 12 having a pushing edge 13 fastened rigidly to the shaft 10. A swing arm 14 is rigidly adjustably fastened thereto by means of screws 1411 through a U-shaped portion 14. The swing arm 14 is pivotally coupled to the coupler by means of a connecting link 15 and a suitably disposed pivot 16 approximately in the longitudinal Center of the coupler 5. Swing arm 14 is pivotally connected to link 15 by pivot 16. The effective crank arm k of the eccentric bushing 4a, the coupler 5 and the drive crank 6 together form a drag-link mechanism. A second system is superposed thereon which consist of the swing arm 14 with the drive rail 12, the connecting link 15 and its pivots which are movable with respect to one another as well as to swing shaft 10 and joint 16. The pushing and pivoting movement of the swing shaft 10 causes the pushing edge 13 to define a curve such as the closed, kidneyshaped path 113 (FIG. 1). A drive pawl 17 for each typebar (not shown) and having a pushing tongue 117 is situated opposite the pushing edge 13, so as to be actuated by the pushing edge 13 when they are in the selected position.

The following description relates to the members of a drive mechanism.

Each drive pawl 17 is pivotally connected at its lower end by means of a molded hinge pin 17a to a longitudinal slot 19a of an associated intermediate lever 19 which is rigidly mounted on a shaft 19, to which a typebar should be imagined as being attached by means ofa pulley wire.

A continuous or separated abutment cushion 20 )FIG. 1) is associated with the intermediate levers 19 to fix their rest position.

A tension spring 18 normally pulls the drive pawls 17 counterclockwise, as seen in FIG. 1, and brings its pawl head 17b into a rest position so that it abuts at a slotted ledge with its associated limit abutment 26 (FIG. 1). A key lever 27 is arranged so that its member 27a will pass through the slot in ledge 25. An abutment cushion 20 retains key lever 27 in the clockwise direction.

A trigger 29 for a one-revolution clutch is disposed below the slotted ledge 25 and abuts member 26. The members connecting it with the clutch connected with the main shaft 2 are not shown and may be like those shown in the Salzberger et al. US. Pat. No. 2,059,537, dated Nov. 3, I936.

A tension spring 30 suspended at one end in an eye defined in protrusion 6a at the bottom of the drive crank 6 and at the other end in an adjustable suspension element 31 in the frame 1. Element 31 may be a grooved screw and pulls the crank 6 and the connected links, particularly the drive rail 12 toward the left and, thus, supports the drive. Shaft 8 is also provided with a freely pivotal detent lever 32 which is pulled together with its detent roller 33 by a tension spring 34 against the disc 3 to hold it in engagement in the detent groove 3a in the disc 3, so that a definite rest position is defined.

The eccentric bushing 4a mounted on the crankpin 4 (FIG. 3) is firmly attached to a link 35 which is pivotally connected by means of a hinge pin 36 and suitable adjustment members, preferably a coupler 37 and a sliding block crank 38, to a bearing pin 40. Teeth 43 of a transfer lever 42, which is mounted on a supporting bolt 44 fastened to a conventional switchable typebar segment carrier (not shown), engage with teeth 39 of the longitudinally displaceable sliding block crank 38, which is guided by guide rods 41 fastened to the typebar segment carrier. A connecting rod 45 leads to a setting and arresting lever 50, which is preferably attached to the side of the keyboard and which serves to adjust the sliding block crank 38 and, thus, the eccentric bushing 40 in view of the number of carbon copies to be made, or with respect to other conditions. The lever is pivoted at 51 and has a finger piece 52 projecting through an opening ofa plate 53 secured to the keyboard. The regulating lever 50 is spring-biased sidewise and is set so that its finger piece 52 normally is pressed into one or another of the detent notches 54 formed on one side of the opening of plate 53 (FIG. 2). The notches 54, of which there may be four, serve to hold the lever 50 in different stations. The lever may be sprung slightly toward the left out of its set position for shifting it from one notch to another.

With lever 50 positioned in the left detent notch 54 the drive rail 12 with the pushing edge 13 stand in the full line, FIG. 2, position. This is the position for the greatest momentum of the type section. But with the lever positioned in the right detent notch 54, FIG. 2, the link 35 with bushing 4a and the drive rail 12 with pushing edge 13 will have been rotated clockwise, shown in FIG. 2 by the dotted orientation. The pushing edge 13 is now farthest from the pushing tongue 117 of the drive pawl 17. This is the position ofleast momentum of the type bar at the instant of printing in that the pushing edge 13 is connected later with the pushing tongue 117 and there results a correspondingly lesser force of the type action at the instant of printing. Intermediate adjustments are effected by placing the lever 50 in one or another of the intermediate detent notches 54.

The mode of operation of a drive mechanism according to the present invention is as follows:

Actuation ofa selector device symbolized by a key lever 27 having a pressure tongue 27a pushes the pawl head 17b of the respective drive pawl 17 downward from position I to position II (FIG. 1). The simultaneously occurring release of the onerevolution clutch (not shown) by trigger 29 causes the main shaft 2 to rotate in the counterclockwise direction, the crank drive imparts movement to the coupler 5 first toward the left and immediately thereafter toward the right, the sinusoidal drive making this movement smooth; the drive rail 12, which was simultaneously put in motion, engages with its pushing edge 13 on the upper curve path ofthe drive tongue 117 (position II, shown in dashed lines) which has been pivoted to within its range and throws the selected drive pawl 17 toward the rear, i.e., in the working or outward direction, thereby ac celerating the intermediate lever 19 with the attached typebar (not shown). In order to permit this typebar to pass the last part of the path before the printing operation in a favorable manner in free flight, the pushing edge 13 releases from tongue 117 due to the design of the pushing edge path 113, approximately one-sixth of the path length before the rear, or outward, return end 113a and is then brought toward the front return end 113b on the lower curve of the path. Because of this decisive path of movement, the pushing edge 13 lies so low that not only the tongue 117 of the above-mentioned selected drive pawl 17 is definitely held outside of the range of the returning pushing edge 13 during its return movement and, thus, causes no interference, but also a second important effect is here also guaranteed. That is, by early depression of the next key lever 27, the associated drive pawl 17 is brought into the preselected position, i.e., its tongue 117 is brought into position II without coming into the range of the stillreturning pushing edge 13. This overlap of movement in time, which acts as a storage, thus permits very fast typing and a substantial gain of time.

The already described release of tongue 117 from the pushing edge 13 terminates the forced driving by the pushing edge 13 and the drive pawl 17 is pivoted upwardly, after the im petus has been absorbed during printing on the platen, by the tension of spring 18, so that it comes to rest against the slotted ledge 25.

After passing through the front return end 113b, the pushing edge 13 returns to the upper portion of its curve path 113, grips the tongue 117 of the preselected drive pawl 17 which is in readiness, and the cycle begins again.

A first adjustment of the distance of the pushing edge 13 from the drive tongues 117 is accomplished by releasing screws 14a in the U-shaped bend 141 of the swing lever 14. Now the swing shaft 10 together with the drive rail 12 and pushing edge 13 can be rotated as desired and the new position can be secured by tightening screws 1411.

A second regulation which is necessary with high-quality typewriters serves to adapt the striking force during typing of letters in the normal and shifted position. In spite of the respectively different actual sizes, the color density of the character imprint must remain as uniform as possible.

This adjustment is accomplished by pivoting the crank 35 at the eccentric bushing 4a which results in a displacement of the coupler 5 and, thus, the coupled pushing edge 13 with respect to the drive tongues 117. Crank 35 receives its impulses from the slidingblock crank 38 which, in engagement with the respective arresting transfer lever 42, takes part in the up and down movement of the switchable typebar segment carrier through its supporting bolt 44. Thus, the driveposition of the eccentric bushing 4a for the drive rail 12 is changed for typing in normal and shifted positions, particularly for lower and upper case letters.

The normal position of the switchable typebar segment carrier is shown in FIG. 2 in full lines. When the typebar segment carrier is moved into the shifted position the crank 35 with the eccentric bushing 4a and the drive rail 12 with the pushing edge 13 will be rotated counterclockwise, shown in FIG. 2 by the dotted outline. The pushing edge 13 stands in the extreme position for greatest force of the type action at the instant of printing. It will be seen now that the typebar segment carrier has automatically determined increased force of poweroperated type section.

The adaptation to the varying number of carbon copies or other conditions is accomplished by height adjustment of the starting position of the sliding block crank 38 which is effected by the toothed transfer lever 42 with its pivoting produced by the displacement of the above-mentioned setting and arresting lever together with the connecting rod 45, The position of the eccentric bushing 4a for normal and shifted positions corresponding to the double arrow next to the supporting bolt is now influenced as described above.

The advantages to be realized with the present invention consist particularly in that the crank drive produces a positive, i.e., always uniform, sinusoidal movement of the drive members. This movement is smooth and has a particularly favorable effect on the drive rail and, thus, avoids peak stresses of the components and joints. This increases the economical operation of the system in that careful dimensioning of the components can keep its masses within favorable limits, to which the production of suitable components, e.g., the drive pawls of a suitable resistant synthetic resins of the acetal plastic group, more particularly, a synthetic resin such as is sold by Du Pont under the trademark Delrin, is a contributing factor permitting the use of high-drive speeds. The smooth operation also results in a noticeable noise reduction.

The proposed arrangement is also very economical in operation, since it permits the production of the exact coupling curve movement of the pushing edge 13 of the drive rail 12 with a drive mechanism present only on one side of the machine, so that the number of components is held relatively low and space is conserved in the always limited space available in powerdriven typewriters. Moreover, the manually accomplished adjustments are limited to one side of the machine.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

1. A typebar drive mechanism for a plurality of typebars comprising, in combination:

a. a reciprocating drive means having an outward and a return movement;

b. a drive rail rotatably mounted on said drive means and having a pushing edge, said rail being mounted on said drive means to execute an outward and return stroke such that the outward and return movement of said drive means causes said pushing edge to follow different paths sun during the outward and return strokes respectively; and

c. a drive pawl for each typebar and each pawl having a pushing tongue arranged to be actuated by said pushing edge during the outward stroke of said drive rail when the respective typebar has been selected with the return stroke of said pushing edge arranged with respect to the outward stroke thereof as a result of said drive rail mounting so that the drive pawl of the next'selected typebar can be actuated before the drive rail has returned.

2. A mechanism as defined in claim 1, further including a drag link mechanism which includes said reciprocating drive means and a coupler link, and a connecting link, pivotally connecting said drive rail to said coupler link.

3. A mechanism as defined in claim 2, further including a swing arm member pivotally connected with said drive rail and said connecting link and wherein the speed ratio for the drag link mechanism is so selected that said pushing edge of said drive rail describe the different paths during the outward and return movements of said pushing edge and together describe a closed, kidney-shaped path.

-4. A mechanism as defined in claim 3, further including a frame structure, a main shaft supported on said frame structure a disc element mounted concentrically on said main shaft, with said disc element having a crankpin extending therefrom and a detent groove in its periphery and in a direction radially outward from said main shaft and providing a pivot point for said coupler link, so that the distance between said crankpin and said main shaft forms a crank arm of said drag link mechanism, a pivotally mounted detent lever with one end thereof supported on said frame structure and the other end thereof having a detent roller mounted thereon, and means biasing said detent lever against the periphery and into the detent groove of said disc.

5. A mechanism as defined in claim 4 further including means for adjusting the distance between said pushing edge and a respective pushing tongue.

6. A mechanism as defined in claim 5 wherein said adjusting means varies the position of said drag link mechanism for the purpose of changing the distance between said pushing edge and a respective pushing tongue in dependence on the selected typebar and on the number of carbon copies.

7. A mechanism as defined in claim 6 further including an eccentric bushing rigidly attached to the end of said coupler link attached to said crankpin and adjustable for the purpose of changing the position of the drag link mechanism, and a crank element being rigidly attached to said eccentric bushing around said crankpin.

8. A mechanism as defined in claim 7 further including coupling means connected to the end of said crank element opposite the end connected to said eccentric bushing and a sliding block crank connected to said coupling at a point opposite the connection to said crank element, so that the eccentric bushing may be adjusted.

9. A mechanism as defined in claim 8 wherein said sliding block crank is longitudinally movable and is provided with teeth, and further including a transfer lever provided with teeth which mesh with the teeth of said sliding block crank and which is mounted for reciprocal movement by a switchable typebar segment carrier and for pivotal movement by a connecting rod to vary the copy set.

10. A mechanism as defined in claim 5, further including a swing shaft and means adjustably fastening said swing shaft and said swing arm, and wherein said drive rail is permanently connected to said swing shaft, so that its position may be adjusted by varying said adjusting means. 

1. A typebar drive mechanism for a plurality of typebars comprising, in combination: a. a reciprocating drive means having an outward and a return movement; b. a drive rail rotatably mounted on said drive means and having a pushing edge, said rail being mounted on said drive means to execute an outward and return stroke such that the outward and return movement of said drive means causes said pushing edge to follow different paths during the outward and return strokes respectively; and c. a drive pawl for each typebar and each pawl having a pushing tongue arranged to be actuated by said pushing edge during the outward stroke of said drive rail when the respective typebar has been selected with the return stroke of said pushing edge arranged with respect to the outward stroke thereof as a result of said drive rail mounting so that the drive pawl of the nextselected typebar can be actuated before the drive rail has returned.
 2. A mechanism as defined in claim 1, further including a drag link mechanism which includes said reciprocating drive means and a coupler link, and a connecting link, pivotally connecting said drive rail to said coupler link.
 3. A mechanism as defined in claim 2, further including a swing arm member pivotally connected with said drive rail and said connecting link and wherein the speed ratio for the drag link mechanism is so selected that said pushing edge of said drive rail describe the different paths during the outward and return movements of said pushing edge and together describe a closed, kidney-shaped path.
 4. A mechanism as defined in claim 3, further including a frame structure, a main shaft supported on said frame structure a disc element mounted concentrically on said main shaft, with said disc element having a crankpin extending therefrom and a detent groove in its periphery and in a direction radially outward from said main shaft and providing a pivot point for said coupler link, so that the distance between said crankpin and said main shaft forms a crank arm of said drag link mechanism, a pivotally mounted detent lever with one end thereof supported on said frame structure and the other end thereof having a detent roller mounted thereon, and means biasing said detent lever against the periphery and into the detent groove of said disc.
 5. A mechanism as defined in claim 4 further including means for adjusting the distance between said pushing edge and A respective pushing tongue.
 6. A mechanism as defined in claim 5 wherein said adjusting means varies the position of said drag link mechanism for the purpose of changing the distance between said pushing edge and a respective pushing tongue in dependence on the selected typebar and on the number of carbon copies.
 7. A mechanism as defined in claim 6 further including an eccentric bushing rigidly attached to the end of said coupler link attached to said crankpin and adjustable for the purpose of changing the position of the drag link mechanism, and a crank element being rigidly attached to said eccentric bushing around said crankpin.
 8. A mechanism as defined in claim 7 further including coupling means connected to the end of said crank element opposite the end connected to said eccentric bushing and a sliding block crank connected to said coupling at a point opposite the connection to said crank element, so that the eccentric bushing may be adjusted.
 9. A mechanism as defined in claim 8 wherein said sliding block crank is longitudinally movable and is provided with teeth, and further including a transfer lever provided with teeth which mesh with the teeth of said sliding block crank and which is mounted for reciprocal movement by a switchable typebar segment carrier and for pivotal movement by a connecting rod to vary the copy set.
 10. A mechanism as defined in claim 5, further including a swing shaft and means adjustably fastening said swing shaft and said swing arm, and wherein said drive rail is permanently connected to said swing shaft, so that its position may be adjusted by varying said adjusting means. 